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Repetitive Acoustic Streaming Patterns in Sinusoidal Shaped Microchannels

Jannesar Elnaz Attar, Hamzehpour Hossein

Archives of Acoustics

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2020

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Vol. 45, No. 1

35--48

EN

Geometry of the fluid container plays a key role in the shape of acoustic streaming patterns. Inadvertent vortices can be troublesome in some cases, but if treated properly, the problem turns into a very useful parameter in acoustic tweezing or micromixing applications. In this paper, the effects of sinusoidal boundaries of a microchannel on acoustic streaming patterns are studied. The results show that while top and bottom sinusoidal walls are vertically actuated at the resonance frequency of basic hypothetical rectangular microchannel, some repetitive acoustic streaming patterns are recognised in classifiable cases. Such patterns can never be produced in the rectangular geometry with flat boundaries. Relations between geometrical parameters and emerging acoustic streaming patterns lead us to propose formulas in order to predict more cases. Such results and formulations were not trivial at a glance.

2

On the Nonlinear Distortions of Sound and its Coupling with Other Modes in a Gaseous Plasma with Finite Electric Conductivity in a Magnetic Field

Perelomova A.

Archives of Acoustics

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2016

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Vol. 41, No. 4

691--699

EN

Nonlinear phenomena of the planar and quasi-planar magnetoacoustic waves are considered. We Focus on deriving of equations which govern nonlinear excitation of the non-wave motions by the intense sound in initially static gaseous plasma. The plasma is treated as an ideal gas with finite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. This introduces dispersion of a flow. Magnetoacoustic heating and streaming in the field of periodic and aperiodic magnetoacoustic perturbations are discussed, as well as generation of the magnetic perturbations by sound. Two cases, corresponding to magnetosound perturbations of low and high frequencies, are considered in detail.

3

Acoustic streaming caused by modulated sound and wave packets

Perelomova A.

Archives of Acoustics

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2004

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Vol. 29, no. 4

647-654

EN

The practical applications of sound relate to approximately periodic sounds. It is shown, that theoretical results of acoustic streaming based on a periodic everywhere sound, should be revised in spite of the experimental data demonstrating the essentially different velocities of streaming. A new approach, which allows evaluating the streaming caused by sound of every type, both periodic and non-periodic, leads to similar results. The results of numerical calculations of streaming caused by modulated sound and series of pulses are compared with those given by formulae for a periodic everywhere sound.

4

Acoustic streaming in focal and post focal region

Grelowska G., Kozaczka E.

Hydroacoustics

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2003

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Vol. 6

125--130

EN

The paper presents concise theoretical description of mechanism of acoustic streaming in the field of finite amplitude wave. Special attention was concentrated on acoustic streaming in focal area into a beam produced by a bowl shaped source. A set up used in experimental investigation is also shown. The measurement was carried out at fixed conditions. Its result was compared to the result of calculation based on theory derived from the reasoning presented by W. Nyborg et al.